1. Technical Field
The present invention relates to a water-stop structure for electrical wire for preventing the intrusion of liquids such as water, oil, and the like into the electrical wire, and a method for manufacturing the same.
2. Description of the Related Art
For example, a ground terminal used in an engine room of a vehicle, and electrical wire connected to the ground terminal are assumed to get wet. When there is gap in the electrical wire, the water may pass through the electrical wire to reach the other end side and to get an electric device (e.g., connector) wet on the other end side of the electrical wire, due to weight of water, capillary action, change of air pressure between both ends of the electrical wire, and the like. In order to prevent the electrical wire from getting wet with such water (including a fluid such as oil) passing through the electrical wire, various types of electrical wire water-stop structures have been proposed (refer to Japanese Patent Laid-Open Publication No. 2008-186675 (Patent Literature 1)).
FIG. 8 illustrates the water-stop structure for an electrical wire 100 described in Patent Literature 1, and a terminal (grounding terminal) 150 is mounted to an end terminal of the electrical wire 100.
The electrical wire 100 is formed of a conductor 110 including a plurality of single wires, and an insulation coating portion 120 coating an outer circumference of the conductor 110. The conductor 110 is exposed by peeling off a skin of the insulation coating portion 120 at the end terminal portion.
A terminal 150 is formed of an electrical connection portion 151 and an electrical wire connection portion 155 integrated with the electrical connection portion 151. The electrical connection portion 151 performs connection with an external device (e.g., vehicle), and there is formed a bolt insertion hole 152 into which a bolt is inserted from the external device. The electrical wire connection portion 155 includes a conductor swaging portion 157 for swaging and fixing the conductor 110 of the electrical wire 100, and a coating swaging portion 158 for swaging and fixing the insulation coating portion 120 thereof.
A water-stop agent 170 adheres to an exposed part or the like of the conductor 110, and is also filled in the insulation coating portion 120, by permeation. The permeated water-stop agent 170 prevents the intrusion of water into the electrical wire 100.
FIG. 9 also illustrates an electrical wire water-stop device 200 described in the Patent Literature 1, and FIG. 10 illustrates a state where, in the electrical wire water-stop device 200, the water-stop agent 170 permeates the insulation coating portion 120. As illustrated in FIG. 9, in the electrical wire water-stop device 200, the electrical wire 100 is set in a treatment chamber 201 that can be sealed, and then the water-stop agent 170 is filled. A water-stop agent dropping device 202 for dropping the water-stop agent is provided in the treatment chamber 201. Furthermore, an air supply device 203 is provided at a side wall part, and an exhaust device 204 is provided at a bottom wall part.
As simple description of water-stop treatment, first, the terminal 150 is positioned in the treatment chamber 201. Subsequently, the liquid water-stop agent 170 is dropped between the conductor swaging portion 157 and the insulation portion swaging portion 158 from the water-stop agent dropping device 202. At a same time or after dropping the water-stop agent 170, pressurized air is supplied into the treatment chamber 201 from the air supply device 203 to thereby make a high-pressure state in the treatment chamber 201. Then, as illustrated in FIG. 10, the water-stop agent 170 permeates the gap in the insulation coating portion 120 by pressure of pressurized air 300. Subsequently, the exhaust device 204 decreases the pressure in the treatment chamber 201 to finish the treatment. The water-stop agent 170 is hardened by humidity in the air.
Whether or not the water-stop agent 170 is filled in the insulation coating portion 120 without the gap is determined by checking an adherence state of the water-stop agent 170 to a surface of the conductor 110 or the like.